Tony Meola's Sidekicks Soccer is a soccer game by Sculptured Software, which uses the same gameplay engine as NCAA Basketball and NHL Stanley Cup Hockey. I guess Nintendo decided to skip publishing the game, and instead Electro Brain picked it up.

The prototype of the game is fairly close to being final. The gameplay and options are pretty much identical. There are some minor graphical changes, such as a different soccer ball image in the menu screen, different fonts for the city team names, and changing the icon over top of the player's selected player. When you score a goal in the final version, the team that scored has a victory celebration, while nothing happens the prototype. The flag for the Netherlands team is glitched in the prototype - I suspect bitrot or improper dumping of the second chip (the dump does not match the B3D6 checksum value on the label). The final game has a slight loading time between the different game option screens that doesn't exist in the prototype. There are also several player names that are changed, which are listed below:

Chinese team: player named Dung in prototype, Deng in final

Italian team has several changes; Pollux/Pollo, Yolanda/Gucci, Mithradatio/DeAngelis

Pakistan team: Maloof/Malouf

Romania team: Choceskue/Wonucia

This game doesn't win any awards for presentation, so I doubt there are any other major differences.

Prototype - Italian Team names

Final - Italian Team names. Also note the soccer ball icon is different

Prototype - note the messed up graphics for the Netherlands

Final version

Prototype

Final - note the smaller font for the team names

Prototype gameplay - note that the player you control has a white dot over top